Diwan Deepti, Komazaki Shun, Suzuki Miho, Nemoto Naoto, Aita Takuyo, Satake Akiko, Nishigaki Koichi
Graduate School of Science and Engineering, Department of Functional Materials Science, Saitama University, Saitama 338-8570, Japan.
BMC Genomics. 2014 Feb 19;15:142. doi: 10.1186/1471-2164-15-142.
Even in the age of next-generation sequencing (NGS), it has been unclear whether or not cells within a single organism have systematically distinctive genomes. Resolving this question, one of the most basic biological problems associated with DNA mutation rates, can assist efforts to elucidate essential mechanisms of cancer.
Using genome profiling (GP), we detected considerable systematic variation in genome sequences among cells in individual woody plants. The degree of genome sequence difference (genomic distance) varied systematically from the bottom to the top of the plant, such that the greatest divergence was observed between leaf genomes from uppermost branches and the remainder of the tree. This systematic variation was observed within both Yoshino cherry and Japanese beech trees.
As measured by GP, the genomic distance between two cells within an individual organism was non-negligible, and was correlated with physical distance (i.e., branch-to-branch distance). This phenomenon was assumed to be the result of accumulation of mutations from each cell division, implying that the degree of divergence is proportional to the number of generations separating the two cells.
即使在下一代测序（NGS）时代，单一生物体内的细胞是否具有系统性独特基因组仍不明确。解决这个与DNA突变率相关的最基本生物学问题之一，有助于阐明癌症的基本机制。
通过基因组图谱分析（GP），我们在个体木本植物的细胞间检测到了基因组序列中相当大的系统性差异。基因组序列差异程度（基因组距离）从植物底部到顶部呈现系统性变化，以至于在最上部枝条的叶片基因组与树的其余部分之间观察到最大的差异。在吉野樱和日本山毛榉树中均观察到了这种系统性变化。
通过GP测量，个体生物体内两个细胞之间的基因组距离不可忽略，且与物理距离（即枝与枝之间的距离）相关。这种现象被认为是每次细胞分裂积累突变的结果，这意味着差异程度与分隔这两个细胞的代数成正比。
